Refrigerator and method of controlling a refrigerator

ABSTRACT

A method of controlling a refrigerator includes starting a first cooling cycle to cool a first storage compartment by operating a compressor and a first fan, determining whether a start condition of a second cooling cycle to cool a second storage compartment is satisfied, operating a second fan for the second storage compartment when the start condition of the second cooling cycle is satisfied, determining whether an output change condition of the second fan is satisfied while the second fan operates, and changing a speed of the second fan when the output change condition of the second fan is satisfied.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to KoreanApplication No. 10-2017-0144536, filed on Nov. 1, 2017, whose entiredisclosure is hereby incorporated by reference.

BACKGROUND 1. Field

A refrigerator and a method for controlling a refrigerator are disclosedherein.

2. Background

Refrigerators are home appliances that may store food or other objectsat a low temperature. A storage compartment may be maintained at aconstant low temperature. In the case of household refrigerators, thestorage compartment may be maintained at a temperature within an upperlimit temperature and lower limit temperature range on the basis of aset temperature.

The refrigerator may be controlled by a method such that when thestorage compartment increases to the upper limit temperature, arefrigeration cycle operates to cool the storage compartment, and whenthe storage compartment reaches the lower limit temperature, therefrigeration cycle is stopped. Refrigerators have been developed inwhich an evaporator is installed in a freezing compartment and arefrigerating compartment. Such a refrigerator may allow the refrigerantto flow to one evaporator of each of the freezing compartment and therefrigerating compartment and then to flow to the other evaporator.

A control method for the aforementioned refrigerator is disclosed inKorean Patent Registration No. 10-1576686 (Registrated on Dec. 4, 2016),whose disclosure is hereby incorporated by reference in its entirety. Inthe control method, after a refrigerating compartment valve and arefrigerating compartment fan operate to cool the refrigeratingcompartment, a freezing compartment valve and a freezing compartment fanmay operate to cool the freezing compartment.

Also, after the cooling of the freezing compartment is completed, thecompressor may be stopped. As such, the freezing compartment fan mayrotate to reduce a temperature of the freezing compartment by latentheat of evaporation.

However, in the related art, although the temperature of the freezingcompartment decreases when the compressor is stopped, the temperature ofthe refrigerating compartment may not decrease. The freshness of foodstored in the refrigerating compartment may be higher as a variation intemperature of the refrigerating compartment is smaller. If thefreshness of the foods is high, a storage period of the foods mayincrease.

However, in the related art, when the compressor is stopped, thetemperature of the refrigerating compartment may continuously increaseuntil the compressor operates again to cool the refrigeratingcompartment. When the compressor operates again, the temperature of therefrigerating compartment may decrease which may increase a variation ofthe temperature. Thus, the freshness of the foods stored in therefrigerating compartment may be deteriorated.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 is a perspective view of a refrigerator according to anembodiment;

FIG. 2 is a perspective view of the refrigerator when a door is openedaccording to the embodiment;

FIG. 3 is a schematic view showing the configuration of the refrigeratoraccording to the embodiment;

FIG. 4 is a block diagram of the refrigerator according to theembodiment;

FIG. 5 is a flowchart illustrating a method of controlling arefrigerator according to an embodiment; and

FIG. 6 is a diagram showing temperature change of a storage compartmentaccording to the method.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 4, the refrigerator 1 may include a cabinet 10that forms an appearance of the refrigerator and doors 11 and 14 movablyconnected to the cabinet 10. A storage compartment in which food isstored may be formed in the cabinet 10. The storage compartment mayinclude a refrigerating compartment 112 and a freezing compartment 111located below the refrigerating compartment 112. The freezingcompartment 111 and the refrigerating compartment 112 may be verticallypartitioned by a partitioning wall 113 in the cabinet 10.

Although a bottom freeze type refrigerator in which a refrigeratingcompartment is placed above a freezing compartment is described in thepresent embodiment, the present embodiment is applicable to arefrigerator in which a refrigerating compartment is placed below afreezing compartment, a refrigerator having only a freezing compartmentor a refrigerator in which a freezing compartment and a refrigeratingcompartment are placed side by side. The doors 11 and 14 may include arefrigerating compartment door 11 that opens and closes therefrigerating compartment 112 and a freezing compartment door 14 thatopens and closes the freezing compartment 111.

The refrigerating compartment door 11 may include a plurality of doors12 and 13 provided side by side. The plurality of doors 12 and 13 mayinclude a first refrigerating compartment door 12 and a secondrefrigerating compartment door 13 arranged adjacent to the firstrefrigerating compartment door 12. The first refrigerating compartmentdoor 12 and the second refrigerating compartment door 13 may moveindependently.

The freezing compartment door 14 may include a plurality of doors 15 and16 arranged adjacent to each other in a vertical direction. Theplurality of doors 15 and 16 may include a first freezing compartmentdoor 15 and a second freezing compartment door 16 located below or abovethe first freezing compartment door 15. The first and secondrefrigerating compartment doors 12 and 13 may rotate and the first andsecond freezing compartment doors 15 and 16 may slide, however, thedisclosure is not limited to this. In another example, the firstfreezing compartment door 15 and the second freezing compartment door 16may be arranged side by side and may rotate.

A dispenser 17 configured to dispense water and/or ice may be providedin any one of the first and second refrigerating compartment doors 12and 13. FIG. 1 shows the dispenser 17 provided in the firstrefrigerating compartment door 12, for example. The dispenser 17 mayalso be provided in any one of the freezing compartment doors 15 and 16.

An ice making compartment configured to make and store ice and an icemaking assembly accommodated in the ice making compartment may beprovided in any one of the first and second refrigerating compartmentdoors 12 and 13. Alternatively, the ice making assembly may be providedin the freezing compartment 111. A cold air inlet 121 and a cold airoutlet 122 may be formed in any one of the first and secondrefrigerating compartment doors.

The ice making assembly may include an ice maker and an ice binconfigured to store ice made in the ice maker. The ice maker may receivecold air of the freezing compartment 11 and may make ice. The ice makingassembly may be implemented by a well-known technology and thus adetailed description thereof will be omitted.

The dispenser 17 and the ice making assembly may be provided in thefirst refrigerating compartment door 12 or the second refrigeratingcompartment door 13. Hereinafter, assume that the dispenser 17 and theice making assembly are provided in the refrigerating compartment door11 including the first refrigerating compartment door 12 and the secondrefrigerating compartment door 13.

An input unit (or input) 18 through which a user may select the type ofice to be dispensed may be provided in the refrigerating compartmentdoor 11. In addition, the dispenser 17 may include an operation pad 19operated by a user in order to dispense water or ice. Alternatively, abutton or a touch panel may be provided in order to input a command fordispensing water or ice.

The refrigerator 1 may further include a compressor 21, a condenser 22,an evaporator 24 for a freezing compartment (or referred to as a “secondevaporator”), which receives the refrigerant from the compressor 21 togenerate cold air to cool the freezing compartment 111, and anevaporator 25 for a refrigerating compartment (or referred to as a“first evaporator), which receives the refrigerant from the compressor21 to generate cold air to cool the refrigerating compartment 112. Therefrigerator 1 may include a switching valve 26 that allows therefrigerant passing through an expansion member 23 to flow to one of theevaporator 24 for the freezing compartment or the evaporator 25 for therefrigerating compartment.

In the present embodiment, the state in which the switching valve 26operates so that the refrigerant flows to the evaporator 24 for thefreezing compartment may be referred to as a first state of theswitching valve 26. Also, the state in which the switching valve 26operates so that the refrigerant flows to the evaporator 25 for therefrigerating compartment may be referred to as a second state of theswitching valve 26. The switching valve 26 may be, for example, a threeway valve.

The refrigerator 1 may further include a freezing compartment fan 28(referred to as a “second cooling fan”) configured to blow air to theevaporator 24 for the freezing compartment, a first motor 27 thatrotates the freezing compartment fan 28, a refrigerating compartment fan29 (referred to as a “first cooling fan”) configured to blow air to theevaporator 25 for the refrigerating compartment, and a second motor 30that rotates the refrigerating compartment fan 29. A series of cycles inwhich the refrigerant flows to a compressor 21, a condenser 22, anexpansion member 23, and the evaporator 24 for the freezing compartmentis referred to as a “freezing cycle”, and a series of cycles in whichthe refrigerant flows to the compressor 21, the condenser 22, theexpansion member 23, and the evaporator 25 for the refrigeratingcompartment is referred to as a “refrigerating cycle”.

The freezing compartment fan 28 may rotate during the freezing cycleoperation, and the refrigerating compartment fan 29 may rotate duringthe refrigerating cycle operation. The compressor 21 may continuouslyoperate during the operation of each of the freezing cycle and therefrigerating cycle.

Although one expansion member 23 is provided at an upstream side of theswitching valve 26 as described above, a first expansion member may beprovided between the switching valve 26 and the evaporator 24 for thefreezing compartment, and a second expansion member may be providedbetween the switching valve 26 and the evaporator 25 for therefrigerating compartment. For another example, a first valve may beprovided at an inlet side of the evaporator 24 for the freezingcompartment, and a second valve may be provided at an inlet side of theevaporator 25 for the refrigerating compartment without using theswitching valve 26. While the freezing cycle operates, the first valvemay be turned on, and the second valve may be turned off. When therefrigerating cycle operates, the first valve may be turned off, and thesecond valve may be turned on.

The refrigerator 1 may further include an ice making fan 31 configuredto blow cold air of the freezing compartment 111 toward the ice makingassembly. The ice making fan 31 may be located in a duct that guidescold air of the freezing compartment 111 toward the ice making assemblyin the freezing compartment 111 or the cabinet 10, without being limitedthereto.

The ice making fan 31 may be interlocked with the freezing compartmentfan 28. That is, the ice making fan 31 may operate when the freezingcompartment fan 28 operates and may be stopped when the freezingcompartment fan 28 is stopped. The refrigerator 1 may further include afreezing compartment temperature sensor 41 configured to sense atemperature of the freezing compartment 111, a refrigerating compartmenttemperature sensor 42 configured to sense a temperature of therefrigerating compartment 112, the input 18 through which the user mayinput a set temperature (or a target temperature) of each of thefreezing compartment 111 and the refrigerating compartment 112, and acontrol unit (or controller) 50 that controls the cooling cycle(including the freezing cycle and the refrigerating cycle) on the basisof the input set temperature and the temperatures sensed by thetemperature sensors 41 and 42.

A temperature less than that set temperature of the freezing compartment111 may be called a first freezing compartment reference temperature (ora lower limit temperature), and a temperature greater than the settemperature of the freezing compartment 111 may be called a secondfreezing compartment reference temperature (or an upper limittemperature). A range between the first freezing compartment referencetemperature and the second freezing compartment reference temperaturemay be called a freezing compartment set temperature range. Although notlimited, the set temperature of the freezing compartment 111 may be amean temperature of the first freezing compartment reference temperatureand the second freezing compartment reference temperature.

A temperature less than that set temperature of the refrigeratingcompartment 112 may be called a first refrigerating compartmentreference temperature (or a lower limit temperature), and a temperaturegreater than the set temperature of the refrigerating compartment 112may be called a second refrigerating compartment reference temperature(or an upper limit temperature). A range between the first refrigeratingcompartment reference temperature and the second refrigeratingcompartment reference temperature may be called a refrigeratingcompartment set temperature range. Although not limited, the targettemperature of the refrigerating compartment 112 may be a meantemperature of the first refrigerating compartment reference temperatureand the second refrigerating compartment reference temperature.

A user may set a set temperature of each of the freezing compartment 111and the refrigerating compartment 112 through the input 18. Thecontroller 50 may control the temperature of the refrigeratingcompartment 112 to be maintained within the set temperature range. Thecontroller 50 may operate the refrigerating cycle when the sensedtemperature of the refrigerating compartment 112 is equal to or greaterthan the reference temperature of the second refrigerating compartment(satisfying a refrigerating cycle start condition), and therefrigerating cycle may be stopped when the sensed temperature of therefrigerating compartment 112 is equal to or below the firstrefrigerating compartment reference temperature (satisfying arefrigerating cycle start condition or a refrigerating cycle stopcondition). When the sensed temperature of the freezing compartment 111is less than the first freezing compartment reference temperature whenthe temperature of the refrigerating compartment 112 is greater than thefirst refrigerating compartment reference temperature while the freezingcycle operates, the freezing cycle may be stopped (the freezing cyclestop condition is satisfied).

The satisfaction of the start condition of the refrigerating cycle maytake precedence over the satisfaction of the stop condition of thefreezing cycle. This is because influence on the freshness of an objectto be stored may be larger when the temperature change difference of therefrigerating compartment is large, as compared to when the temperaturechange difference of the freezing compartment is large.

For example, when the start condition of the refrigerating cycle issatisfied before the stop condition of the freezing cycle is satisfiedduring the operation of the freezing cycle, the freezing cycle may bestopped, and the refrigerating cycle may start. In the presentembodiment, a basic refrigerant cycle for cooling the storagecompartment may be performed in order of a first refrigerating cycle, afreezing cycle, a second refrigerating cycle and compressor stop.

For example, after the first refrigerating cycle operates, the firstrefrigerating cycle may be stopped and the freezing cycle may operate.When the stop condition of the freezing cycle is satisfied, after thesecond refrigerating cycle operates, the compressor 21 may be stoppedfor a predetermined time, or while a specific condition is satisfied. Inthe present embodiment, the second refrigerating cycle may be omitted.In this case, when the freezing cycle is stopped, the compressor 21 maybe stopped for a predetermined time or while a specific condition issatisfied.

In the present embodiment, the basic refrigerant cycle may be performedin order to stabilize the refrigerant cycle. During operation of thefreezing cycle, if the start condition of the refrigerating cycle issatisfied before the stop condition of the freezing cycle is satisfied,the first refrigerating cycle may restart instead of the secondrefrigerating cycle. Thus, the refrigerant cycle may not be stable.Accordingly, the method of controlling the refrigerator according to thepresent embodiment may include a protection logic that allows therefrigerant cycle to stably operate. The protection logic will bedescribed below.

Referring to FIGS. 5 and 6, the refrigerator 1 may be powered on (S1).When the refrigerator 1 is powered on, the refrigerator 1 may cool thefreezing compartment 111 or the refrigerating compartment 112.

Hereinafter, the method of controlling the refrigerator when thefreezing compartment 111 is cooled after cooling the refrigeratingcompartment 112 will be described. In order to cool the refrigeratingcompartment 112, the controller 50 may turn the compressor 21 on androtate the refrigerating compartment fan 29 (S2). In addition, thecontroller 50 may switch the switching valve 26 to a first state suchthat refrigerant flows to the evaporator 25 for the refrigeratingcompartment (S2).

In addition, when the refrigerating cycle operates, the freezingcompartment fan 28 may remain stopped. The refrigerant passing throughthe condenser 22 after being compressed in the compressor 21 may thenflow to the evaporator 25 for the refrigerating compartment through theswitching valve 26. In addition, the refrigerant evaporated whileflowing through the evaporator 25 for the refrigerating compartment mayflow into the compressor 21 again.

In addition, air, which has exchanged heat with the evaporator 25 forthe refrigerating compartment, may be supplied to the refrigeratingcompartment 112. Accordingly, the temperature of the refrigeratingcompartment 112 may decrease but the temperature of the freezingcompartment 111 may increase.

During operation of the refrigerating cycle, the controller 50 maydetermine whether the start condition of the freezing compartment issatisfied (S3). That is, the controller 50 may determine whether thestop condition of the refrigerating cycle is satisfied.

For example, the controller 50 may determine that the start condition ofthe freezing compartment is satisfied, when the temperature of therefrigerating compartment 112 is equal to or less than a firstrefrigerating compartment reference temperature.

Upon determining that the start condition of the freezing compartment issatisfied in step S3, the controller 50 may operate the freezing cycle.For example, the controller 50 may switch the switching valve 26 to asecond state such that the refrigerant flows to the evaporator 24 forthe freezing compartment (S4). Even when the refrigerating cycle isswitched to the freezing cycle, the compressor 21 may continuouslyoperate without being stopped. In addition, the controller 50 may rotatethe freezing compartment fan 28.

As described above, when the freezing compartment fan 28 rotates, theice making fan 31 may also rotate. By rotation of the freezingcompartment fan 28, cold air may be supplied to the freezing compartment111 and cold air of the freezing compartment 111 may be supplied towardthe ice making assembly located in the refrigerating compartment door bythe ice making fan 31.

When operation of the refrigerating cycle starts, the refrigeratingcompartment fan 29 may continuously rotate without being stopped.However, in order to prevent the temperature of the refrigeratingcompartment 112 from rapidly decreasing by rotation of the refrigeratingcompartment fan 29, when the freezing cycle starts, the refrigeratingcompartment fan 29 may be rotated at a lower rotational speed.

For example, the refrigerating compartment fan 29 may rotate at a firstRPM (or first output) while the refrigerating cycle operates and mayrotate at a second RPM (or second output) less than the first RPM whenthe refrigerating cycle is stopped. When the refrigerating compartmentfan 29 is rotated at the second RPM when the refrigerating cycle isstopped, it may be possible to delay the rise of the temperature of therefrigerating compartment 112 during the operation of the freezingcycle.

When the rise of the temperature of the refrigerating compartment 112 isdelayed, a time required for the temperature of the refrigeratingcompartment 112 to reach the second refrigerating compartment referencetemperature may be delayed even when the operation time of the freezingcycle is increased. In addition, when the refrigerating compartment fan29 is rotated at the second RPM when the refrigerating cycle is stopped,it may be possible to minimize the temperature decreasing width of therefrigerating compartment 112 until the refrigerating compartment fan 29is stopped.

When the refrigerating compartment fan 29 continuously rotates when therefrigerating cycle is stopped, the temperature of the refrigeratingcompartment 112 may be decreased to a temperature lower than the firstrefrigerating compartment reference temperature. At this time, when therefrigerating compartment fan 29 is rotated at the second RPM when therefrigerating cycle is stopped, the temperature decreasing width of therefrigerating compartment 112 may be minimized.

As the temperature change difference of the refrigerating compartment112 is decreased, the freshness of the object to be stored may beimproved. It may therefore be possible to minimize a drop in thefreshness of the object to be stored, by minimizing the temperaturechange difference of the refrigerating compartment 112.

The refrigerating compartment fan 29 may be stopped when a predeterminedtime elapses after being rotated at the second RPM (S5). Duringoperation of the freezing cycle, the controller 50 may determine whetherthe speed change condition of the freezing compartment fan 28 issatisfied (S6).

When the freezing cycle starts, the temperature of the freezingcompartment 111 may be equal or similar to the second freezingcompartment reference temperature. In addition, the temperature of thefreezing compartment 111 may be decreased by operation of the freezingcycle.

The controller 50 may determine whether the speed change condition ofthe freezing compartment fan 28 is satisfied, for example, when thetemperature of the freezing compartment 111 reaches a freezingcompartment set temperature M. For example, the controller 50 maydetermine that the speed change condition of the freezing compartmentfan 28 is satisfied, when the temperature of the refrigeratingcompartment 112 is less than a refrigerating compartment set temperatureN.

When the speed change condition of the freezing compartment fan 28 issatisfied, the controller 50 may decrease the rotation speed of thefreezing compartment fan 28 (S7). In the present embodiment, when therotation speed of the freezing compartment fan 28 is decreased, it maybe possible to increase the operation time of the freezing cycle.

Since the ice making fan 31 is interlocked with the freezing compartmentfan 28, when the operation time of the freezing cycle is increased, theoperation time of the ice making fan 31 may be increased, therebyincreasing the amount of ice made in the ice making assembly. At thistime, the rotation speed of the refrigerating compartment fan 28 mayvary according to the temperature of the refrigerating compartment 112.

For example, a first fan reference temperature lower than therefrigerating compartment set temperature N by a reference temperaturevalue and a second fan reference temperature lower than the first fanreference temperature by the reference temperature value may be set.Before the temperature of the freezing compartment 111 reaches thefreezing compartment set temperature M, the freezing compartment fan 28may rotate at a first rotation speed.

When the temperature of the freezing compartment 111 reaches thefreezing compartment set temperature M, if the temperature of therefrigerating compartment 112 is in a range from the refrigeratingcompartment set temperature N to the first fan reference temperature,the freezing compartment fan 28 may rotate at a second rotation speedlower than the first rotation speed. When the temperature of thefreezing compartment 111 reaches the freezing compartment settemperature M, if the temperature of the refrigerating compartment 112is in a range from the first fan reference temperature to the second fanreference temperature, the freezing compartment fan 28 may rotate at athird rotation speed lower than the second rotation speed.

In other words, when the temperature of the freezing compartment 111reaches the freezing compartment set temperature M, as the temperatureof the refrigerating compartment 112 is decreased, the rotation speed ofthe freezing compartment fan 28 may be decreased. As the temperature ofthe refrigerating compartment 112 is decreased, a time required for thetemperature of the refrigerating compartment 112 to reach the secondrefrigerating compartment reference time may be increased.

By maintaining the rotation speed of the freezing compartment fan 28 ata low speed, it may be possible to maximally increase the operation timeof the freezing cycle. It may then be possible to increase the amount ofice made in the ice making assembly and to decrease the temperaturechange difference of the refrigerating compartment 112.

In contrast, as the result of determination of step S6, even when thetemperature of the freezing compartment 111 reaches the freezingcompartment set temperature M, if the temperature of the refrigeratingcompartment 112 is equal to or greater than the refrigeratingcompartment set temperature N, the controller 50 may determine that thespeed change condition of the freezing compartment fan 28 is notsatisfied (protection logic 1). In this case, the rotation speed of thefreezing compartment fan 28 may be maintained at a previous speed.

When the temperature of the refrigerating compartment 112 is equal to orgreater than the refrigerating compartment set temperature N, since atime required for the temperature of the refrigerating compartment 112to reach the second refrigerating compartment reference temperature isshort, the temperature of the freezing compartment 111 may rapidlydecrease before the temperature of the refrigerating compartment 112reaches the second refrigerating compartment reference temperature. Itmay be possible to prevent the temperature of the refrigeratingcompartment 112 from reaching the second refrigerating compartmentreference temperature before the temperature of the freezing compartment111 reaches the first refrigerating compartment reference temperature(protection logic 1).

The controller 50 may determine that the forced termination condition ofthe freezing cycle is satisfied during operation of the freezing cycle(S8) (protection logic 2). For example, the controller 50 may determinethat the forced termination condition of the freezing cycle is satisfiedwhen the temperature of the refrigerating compartment 112 is equal to orgreater than a first termination reference temperature N+a which ishigher than the refrigerating compartment set temperature N and lowerthan the second refrigerating compartment reference temperature and thetemperature of the freezing compartment 111 is equal to or less than asecond termination reference temperature M−b which is lower than thefreezing compartment set temperature M and higher than the firstfreezing compartment reference temperature.

When the freezing cycle is forcibly terminated, the start condition ofthe refrigerating cycle may not be satisfied before the stop conditionof the freezing cycle is satisfied. At this time, since the temperatureof the freezing compartment 111 is close to the first freezingcompartment reference temperature, even if the freezing cycle isforcibly terminated, the temperature of the freezing compartment 111 maybe maintained in the freezing compartment set temperature.

The controller 50 may determine whether the normal stop condition of thefreezing cycle is satisfied (S9) when the forced termination conditionof the freezing cycle is not satisfied. When the normal stop conditionof the freezing cycle is satisfied, the temperature of the freezingcompartment 111 may be equal to or less than the first freezingcompartment reference temperature.

If the forced termination condition of the freezing cycle is satisfiedin step S8 or if the stop condition of the freezing cycle is satisfiedin step S9, the freezing cycle may be stopped. The freezing compartmentfan 28 may then be stopped and the switching valve 26 may be switched tothe first state. In addition, the refrigerating compartment fan 29 mayrotate (the second refrigerating cycle may be performed) (S10).

The refrigerating compartment fan 29 may be stopped after being rotatedfor a first reference time period and the switching valve 26 may beturned off after a second reference time period less than the firstreference time period. When the switching valve 26 is turned off, thecompressor 21 may also be stopped. In other words, after the switchingvalve 26 is turned off, the refrigerating compartment fan 29 may befurther rotated for a predetermined time and then the refrigeratingcompartment fan 29 may be stopped.

When the second refrigerating cycle starts after the freezing cycle isstopped, it may be possible to delay a rise of the temperature of therefrigerating compartment 112 in a period in which the compressor isstopped after the second refrigerating cycle. The controller 50 maydetermine whether the start condition of the refrigerating cycle issatisfied when the compressor 21 is turned off (S11). Upon determiningthat the start condition of the refrigerating cycle is satisfied in stepS11, the refrigerating cycle starts (returns to step S2) unless power isturned off (S12).

In this specification, the refrigerating compartment may be referred toas a first storage compartment and the freezing compartment may bereferred to as a second storage compartment. The refrigerating cycle maybe referred to as a first cooling cycle for the first storagecompartment and the freezing cycle may be referred to as a secondcooling cycle for the second storage compartment. The firstrefrigerating cycle may be referred to as a first cooling cycle and thesecond refrigerating cycle may be referred to as a second cooling cycle.

In addition, the refrigerating compartment fan 29 may be referred to asa first cold air supply unit for the first storage compartment and thefreezing compartment fan 28 may be referred to as a second cold airsupply unit for the second storage compartment. An increase in rotationspeed of the refrigerating compartment fan and/or the freezingcompartment fan may be referred to as an increase in output of the coldair supply unit and a decrease in rotation speed of the refrigeratingcompartment fan and/or the freezing compartment fan may be referred toas a decrease in output of the cold air supply unit.

Although the refrigerator in which two cooling cycles are configuredusing one compressor and two evaporators is described in the aboveembodiment, the control method for decreasing the temperature changewidth of the storage compartment of the present embodiment is applicableto a refrigerator in which two cooling cycles are configured using twocompressors and two evaporators. In this case, the cold air supply unitmay include fans (a refrigerating compartment fan and a freezingcompartment fan) that blow air to compressors (a compressor for afreezing compartment and a compressor for a refrigerating compartment)and evaporators (an evaporator for a freezing compartment and anevaporator for a refrigerating compartment).

The present embodiment provides a refrigerator which is controlled toreduce a variation in temperature of a storage chamber so as to improvefreshness of a stored object and a control method therefor. The presentembodiment provides a refrigerator capable of increasing the amount ofmade ice while reducing temperature change of a storage compartment, anda control method therefor.

A method of controlling a refrigerator may include starting a firstcooling cycle to cool a first storage compartment to operate acompressor and operating a first cold air supply unit for the firststorage compartment, determining whether a start condition of a secondcooling cycle to cool a second storage compartment is satisfied,operating a second cold air supply unit for the second storagecompartment when the start condition of the second cooling cycle issatisfied, determining whether an output change condition of the secondcold air supply unit is satisfied while the second cold air supply unitoperates, and changing output of the second cold air supply unit whenthe output change condition of the second cold air supply unit issatisfied.

A refrigerator may include a compressor, a condenser configured tocondense refrigerant discharged from the compressor, an evaporator for afreezing compartment and an evaporator for a refrigerating compartmentbranched from an outlet side of the condenser, a switching valveconfigured to allow the refrigerant to flow to any one of the evaporatorfor the freezing compartment and the evaporator for the refrigeratingcompartment, a freezing compartment fan configured to allow air to flowto the evaporator for the freezing compartment, a refrigeratingcompartment fan configured to allow air to flow to the evaporator forthe refrigerating compartment, and a controller configured to controlthe switching value and each of the fans.

When a refrigerating cycle operates, the controller may allow therefrigerant to flow to the evaporator for the refrigerating compartmentby the switching valve and may allow the refrigerating compartment fanto be rotated, and, when a freezing cycle operates, the controller mayallow the refrigerant to flow to the evaporator for the freezingcompartment by the switching valve and may allow the freezingcompartment fan to be rotated. During operation of the freezing cycle,the controller may determine that a speed change condition of thefreezing compartment fan is satisfied and may decrease a rotation speedof the freezing compartment fan when the speed change condition of thefreezing compartment fan is satisfied.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layers.In contrast, when an element is referred to as being “directly on”another element or layer, there are no intervening elements or layerspresent. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section could be termed a second element,component, region, layer or section without departing from the teachingsof the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “lower” relative to other elements or features would then be oriented“upper” relative the other elements or features. Thus, the exemplaryterm “lower” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the disclosure are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the disclosure.As such, variations from the shapes of the illustrations as a result,for example, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the disclosure should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A method of controlling a refrigerator, themethod comprising: starting a first cooling cycle that cools a firststorage compartment by operating a compressor and a first fan;determining whether a start condition of a second cooling cycle thatcools a second storage compartment is satisfied; operating a second fanfor the second storage compartment when the start condition of thesecond cooling cycle is satisfied; determining whether an output changecondition of the second fan is satisfied while the second fan operates;and changing a speed of the second fan when the output change conditionof the second fan is satisfied.
 2. The method of claim 1, wherein theoutput change condition of the second fan is satisfied when atemperature of the second storage compartment reaches a predeterminedtemperature M between an upper limit temperature and a lower limittemperature of the second storage compartment.
 3. The method of claim 2,wherein the set temperature M is an average temperature of the upperlimit temperature and the lower limit temperature.
 4. The method ofclaim 2, wherein when a temperature of the first storage compartment islower than a set temperature N between an upper limit temperature and alower limit temperature of the first storage compartment, the outputchange condition of the second fan is satisfied.
 5. The method of claim4, wherein when the output change condition of the second fan issatisfied, the speed of the second fan is decreased.
 6. The method ofclaim 5, wherein when the output change condition of the second fan issatisfied, a degree of decrease in the speed of the second fan isvariable according to the temperature of the first storage compartment.7. The method of claim 4, wherein when the temperature of the firststorage compartment is higher than the set temperature N between theupper limit temperature and the lower limit temperature of the firststorage compartment, the speed of the second fan is maintained orincreased.
 8. The method of claim 1, wherein the second storagecompartment is a freezing compartment and the second fan is a freezingcompartment fan, and wherein when the freezing compartment fan operates,an ice making fan that supplies cold air of the freezing compartment toan ice making assembly also operates.
 9. The method of claim 1, whereinthe first fan operates at a first speed when the first cooling cycleoperates, and wherein the first fan operates for a predetermined time ata second speed less than the first speed and then is stopped when anoperation of the second cooling cycle starts.
 10. The method of claim 1,further comprising: determining whether a forced termination conditionof the second cooling cycle is satisfied before a temperature of thesecond storage compartment reaches a lower limit temperature of thesecond storage compartment; and stopping the second cooling cycle whenthe forced termination condition of the second cooling cycle issatisfied.
 11. The method of claim 10, wherein the forced terminationcondition of the second cooling cycle is satisfied when a temperature ofthe first storage compartment is equal to or greater than a firsttermination reference temperature N+a higher than a set temperature N ofthe first storage compartment and lower than an upper limit temperatureof the first storage compartment, and the temperature of the secondstorage compartment is equal to or less than a second terminationreference temperature M−b lower than a set temperature M of the secondstorage compartment and higher than a lower limit temperature of thesecond storage compartment.
 12. The method of claim 10, furthercomprising: determining whether a normal stop condition of the secondcooling cycle is satisfied when the forced termination condition of thesecond cooling cycle is not satisfied; and stopping the second coolingcycle when the normal stop condition of the second cooling cycle issatisfied.
 13. The method of claim 12, wherein the normal stop conditionof the second cooling cycle is satisfied when the temperature of thesecond storage compartment is equal to or less than a lower limittemperature of the second storage compartment, and the compressor isstopped when the second cooling cycle is forcibly terminated or normallystopped.
 14. The method of claim 12, wherein a third cooling cycle forthe first storage compartment starts when the second cooling cycle isforcibly terminated or normally stopped.
 15. The method of claim 14,wherein the first fan is rotated for a first reference time and then isstopped when the third cooling cycle starts, and wherein a valveconfigured to supply refrigerant to an evaporator for the first storagecompartment is turned on for a second reference time shorter than thefirst reference time and then is turned off.
 16. A refrigeratorcomprising: a compressor; a condenser configured to condense refrigerantdischarged from the compressor; a first evaporator for a freezingcompartment and a second evaporator for a refrigerating compartment, thefirst and second evaporators being coupled to an outlet side of thecondenser; a switching valve configured to allow the refrigerant to flowto one of the first and second evaporators; a first fan configured tosupply air to the first evaporator; a second fan configured to supplyair to the second evaporator; and a controller configured to control theswitching valve and the first and second fans, wherein when arefrigerating cycle operates, the controller controls the switchingvalve to supply the refrigerant to the second evaporator and turns onthe second fan, wherein when a freezing cycle operates, the controllercontrols the switching valve to supply the refrigerant to the firstevaporator and turns on the first fan, and wherein during an operationof the freezing cycle, an operating speed of the first fan is changedwhen the controller determines at least one condition of at least one ofthe freezing compartment or refrigerating compartment is changedrelative to a desired condition.
 17. The refrigerator of claim 16,wherein during operation of the refrigerating cycle, the refrigeratingcompartment fan is rotated at a first RPM, and when the operation of thefreezing cycle starts, the refrigerating compartment fan is rotated fora predetermined time at a second RPM less than the first RPM and then isstopped.
 18. The refrigerator of claim 16, wherein the controllerdetermines whether a forced termination condition of the freezing cycleis satisfied before a temperature of the freezing compartment reaches alower limit temperature of the freezing compartment, and wherein whenthe forced termination condition of the freezing cycle is satisfied, thecontroller stops the freezing cycle.
 19. The refrigerator of claim 18,wherein if a temperature of the first storage compartment is equal to orgreater than a first termination reference temperature N+a higher than aset temperature N of the first storage compartment and lower than anupper limit temperature of the first storage compartment and thetemperature of the second storage compartment is equal to or less than asecond termination reference temperature M−b lower than a settemperature M of the second storage compartment and higher than a lowerlimit temperature of the second storage compartment, the controllerdetermines that the forced termination condition of the second coolingcycle is satisfied.
 20. The method of claim 18, wherein the controllerdetermines whether a normal stop condition of the cooling cycle issatisfied when the forced termination condition of the cooling cycle isnot satisfied; and stops the cooling cycle when the normal stopcondition of the cooling cycle is satisfied.